Is it possible to stop the animation of a wing accessory using SimPe. If so could some one please give me a few instruction. I just need to know what area of the file to change when it is opened in SimPe.

The altered wings will be used for my own personal use - not uploaded or shared

What animations are you talking about? Accessories don't actually have animations generally, with the exception of maybe the NoodleSoother helmet.

If you are talking about bone assignments that make the accessory move with the sim, its something you need to do in a meshing program like MilkShape, you just need to change the bone assignments to 'head' and it with move with the sim's whole head. Hair assignments and body assignments (not sure if body assignments are possible with accessories, but I wouldn't be surprised) are likely what is causing the movement. Find a joint in the body or head that moves how you want the accessory to act and change it to that.